Listeria monocytogenes in ready to eat meat products from Zambia: phenotypical and genomic characterization of isolates

The contamination of ready to eat foods (RTE) products due to Listeria monocytogenes could compromise the products safety becoming a great risk for the consumers. The high presence of L. monocytogenes in RTE products has been described worldwide, but few data are available about these products from African countries. The aims of this study were to report the presence of L. monocytogenes in Zambian RTE products, providing genomic characterization and data on similarity with African circulating strains using whole genome sequencing (WGS). A total of 304 RTE products, produced by different Zambian manufacturers, were purchased at retail, from major supermarkets located in Lusaka, Zambia, comprising 130 dairy and 174 meat products. L. monocytogenes was detected only in 18 (10.3%) RTE meat products of the 174 samples tested. The MLST analysis grouped the 18 L. monocytogenes isolates in 7 clonal complexes (CCs): CC1 (n = 5), CC2 (n = 4), CC9 (n = 4), CC5 (n = 2), CC121 (n = 1), CC155 (n = 1), and CC3 (n = 1). According to the cgMLST results, several clusters were detected, in particular belonging to hyper-virulent clones CC1 and CC2. Regarding the virulence factors, a complete L. monocytogenes Pathogenicity Island 3 (LIPI-3) was present both in the CC1 and CC3, in addition to LIPI-1. Several resistance genes and mobile genetic elements were detected, including Stress Islands, the bcrABC cassette and Tn6188_qac transposon, plasmids and intact prophages. Despite being a first preliminary work with a limited number of samples and isolates, this study helped to increase existing knowledge on contaminated RTE products in Zambia, confirming the presence of hyper-virulent L. monocytogenes CCs, which could play an important role in human diseases, posing a public health concern for consumers.

Multi-approach methods to predict cryptic carbapenem resistance mechanisms in Klebsiella pneumoniae detected in Central Italy

The rapid emergence of carbapenem-resistant Klebsiella pneumoniae (Kp) strains in diverse environmental niches, even outside of the clinical setting, poses a challenge for the detection and the real-time monitoring of novel antimicrobial resistance trends using molecular and whole genome sequencing-based methods. The aim of our study was to understand cryptic resistance determinants responsible for the phenotypic carbapenem resistance observed in strains circulating in Italy by using a combined approach involving whole genome sequencing (WGS) and genome-wide association study (GWAS). In this study, we collected 303 Kp strains from inside and outside clinical settings between 2018-2022 in the Abruzzo region of Italy. The antimicrobial resistance profile of all isolates was assessed using both phenotypic and bioinformatic methods. We identified 11 strains resistant to carbapenems, which did not carry any known genetic determinants explaining their phenotype. The GWAS results showed that incongruent carbapenem-resistant phenotype was associated specifically with strains with two capsular types, KL13 and KL116 including genes involved in the capsule synthesis, encoding proteins involved in the assembly of the capsule biosynthesis apparatus, capsule-specific sugar synthesis, processing and export, polysaccharide pyruvyl transferase, and lipopolysaccharide biosynthesis protein. These preliminary results confirmed the potential of GWAS in identifying genetic variants present in KL13 and KL116 that could be associated with carbapenem resistance traits in Kp. The implementation of advanced methods, such as GWAS with increased antimicrobial resistance surveillance will potentially improve Kp infection treatment and patient outcomes.

The Slaughterhouse as Hotspot of CC1 and CC6 Listeria monocytogenes Strains with Hypervirulent Profiles in an Integrated Poultry Chain of Italy

In Europe, very few studies are available regarding the diversity of Listeria monocytogenes (L. monocytogenes) clonal complexes (CCs) and sequence types (ST) in poultry and on the related typing of isolates using whole genome sequencing (WGS). In this study, we used a WGS approach to type 122 L. monocytogenes strains isolated from chicken neck skin samples collected in two different slaughterhouses of an integrated Italian poultry company. The studied strains were classified into five CCs: CC1-ST1 (21.3%), CC6-ST6 (22.9%), CC9-ST9 (44.2%), CC121-ST121 (10.6%) and CC193-ST193 (0.8%). CC1 and CC6 strains presented a virulence gene profile composed of 60 virulence genes and including the Listeria Pathogenicity Island 3, aut_IVb, gltA and gltB. According to cgMLST and SNPs analysis, long-term persistent clusters belonging to CC1 and CC6 were found in one of the two slaughterhouses. The reasons mediating the persistence of these CCs (up to 20 months) remain to be elucidated, and may involve the presence and the expression of stress response and environmental adaptation genes including heavy metals resistance genes (cadAC, arsBC, CsoR-copA-copZ), multidrug efflux pumps (mrpABCEF, EmrB, mepA, bmrA, bmr3, norm), cold-shock tolerance (cspD) and biofilm-formation determinants (lmo0673, lmo2504, luxS, recO). These findings indicated a serious risk of poultry finished products contamination with hypervirulent L. monocytogenes clones and raised concern for the consumer health. In addition to the AMR genes norB, mprF, lin and fosX, ubiquitous in L. monocytogenes strains, we also identified parC for quinolones, msrA for macrolides and tetA for tetracyclines. Although the phenotypical expression of these AMR genes was not tested, none of them is known to confer resistance to the primary antibiotics used to treat listeriosis The obtained results increase the data on the L. monocytogenes clones circulating in Italy and in particular in the poultry chain.

High Prevalence of Klebsiella pneumoniae in European Food Products: a Multicentric Study Comparing Culture and Molecular Detection Methods

The Klebsiella pneumoniae species complex (KpSC) is a leading cause of multidrug-resistant human infections. To better understand the potential contribution of food as a vehicle of KpSC, we conducted a multicentric study to define an optimal culture method for its recovery from food matrices and to characterize food isolates phenotypically and genotypically. Chicken meat (n = 160) and salad (n = 145) samples were collected in five European countries and screened for the presence of KpSC using culture-based and zur-khe intergenic region (ZKIR) quantitative PCR (qPCR) methods. Enrichment using buffered peptone water followed by streaking on Simmons citrate agar with inositol (44°C for 48 h) was defined as the most suitable selective culture method for KpSC recovery. A high prevalence of KpSC was found in chicken meat (60% and 52% by ZKIR qPCR and the culture approach, respectively) and salad (30% and 21%, respectively) samples. Genomic analyses revealed high genetic diversity with the dominance of phylogroups Kp1 (91%) and Kp3 (6%). A total of 82% of isolates presented a natural antimicrobial susceptibility phenotype and genotype, with only four CTX-M-15-producing isolates detected. Notably, identical genotypes were found across samples-same food type and same country (15 cases), different food types and same country (1), and same food type and two countries (1)-suggesting high rates of transmission of KpSC within the food sector. Our study provides a novel isolation strategy for KpSC from food matrices and reinforces the view of food as a potential source of KpSC colonization in humans. IMPORTANCE Bacteria of the Klebsiella pneumoniae species complex (KpSC) are ubiquitous, and K. pneumoniae is a leading cause of antibiotic-resistant infections in humans. Despite the urgent public health threat represented by K. pneumoniae, there is a lack of knowledge of the contribution of food sources to colonization and subsequent infection in humans. This is partly due to the absence of standardized methods for characterizing the presence of KpSC in food matrices. Our multicentric study provides and implements a novel isolation strategy for KpSC from food matrices and shows that KpSC members are highly prevalent in salads and chicken meat, reinforcing the view of food as a potential source of KpSC colonization in humans. Despite the large genetic diversity and the low levels of resistance detected, the occurrence of identical genotypes across samples suggests high rates of transmission of KpSC within the food sector, which need to be further explored to define possible control strategies.

Phylogenetic Analysis and Genome-Wide Association Study Applied to an Italian Listeria monocytogenes Outbreak

From May 2015 to March 2016, a severe outbreak due to Listeria monocytogenes ST7 strain occurred in Central Italy and caused 24 confirmed clinical cases. The epidemic strain was deeply investigated using whole-genome sequencing (WGS) analysis. In the interested area, the foodborne outbreak investigation identified a meat food-producing plant contaminated by the outbreak strain, carried by pork-ready-to-eat products. In the same region, in March 2018, the epidemic strain reemerged causing one listeriosis case in a 10-month-old child. The aim of this study was to investigate the phylogeny of the epidemic and reemergent strains over time and to compare them with a closer ST7 clone, detected during the outbreak and with different pulsed-field gel electrophoresis (PFGE) profiles, in order to identify genomic features linked to the persistence and the reemergence of the outbreak. An approach combining phylogenetic analysis and genome-wide association study (GWAS) revealed that the epidemic and reemergent clones were genetically closer to the ST7 clone with different PFGE profiles and strictly associated with the pork production chain. The repeated detection of both clones was probably correlated with (i) the presence of truly persistent clones and the repeated introduction of new ones and (ii) the contribution of prophage genes in promoting the persistence of the epidemic clones. Despite that no significant genomic differences were detected between the outbreak and the reemergent strain, the two related clones detected during the outbreak can be differentiated by transcriptional factor and phage genes associated with the phage LP-114.

Virulence and antibiotic resistance of Klebsiella pneumoniae strains isolated from wastewater

Background

Multidrug-resistant Klebsiella pneumoniae (Kp) strains are considered a global public health threat. The aim of the present study was to assess the occurrence of resistant and virulent Kp in Italian environmental wastewater, in order to evaluate the contribution of wastewater as reservoir of virulent and multidrug-resistant bacteria.

Methods

Forty samples of wastewater were collected in six sampling sessions from June to November 2018 in Central Italy and processed to detect Kp. All the presumptive Kp colonies isolated were identified by MALDI-TOF MS (Bruker Daltonics, Germany), then the genome sequences of all the confirmed Kp were obtained using Illumina Sequencing. Finally, characterization of virulence and resistance genes was performed in silico using the BIGSdb-Kp database provided by the Institut Pasteur (http://bigsdb.web.pasteur.fr).

Results

Kp was detected in 32 out of 40 samples (80%) and all strains were confirmed as Kp by MALDI-TOF MS. Genotyping analysis showed that besides the native bla-SHV, bla-LEN, bla-OKP genes linked to β-lactams resistance, gyr and par genes, involved in quinolone resistance, and no other resistance genes were detected. Regarding virulence, all strains carried the fimbriae encoding gene mrk, associated with adhesion and biofilm formation. The ferric aerobactin receptor iutA was harbored by 3 strains (9.4%). The siderophore Yersiniabactin locus (ybtS, ybtX, ybtQ, ybtP, ybtA, irp2 irp1, ybtU, ybtT, ybtE, fyuA), essential for iron scavenging, is carried by 7 out of 32 strains (21.9%).

Conclusions

Our results showed a high prevalence of Kp in wastewater that also harbored several resistance and virulence genes. These results make interesting to investigate more about wastewater as hot spots of enrichment, recombination, genetic exchange and selection of antibiotic resistant “super-bugs” that persisting and surviving in the environment could be a health risk for humans and animals.

Key messages

Wastewater could play a role as Klebsiella pneumoniae reservoir of virulence and resistance genes that can disseminate into wildlife and reach humans. It’s necessary a “one health” approach to deeply investigate about the presence of superbugs bacteria in the environment and the possible risks for human health.

Fast WGS source attribution of Listeria monocytogenes outbreak in a sheep flock in Abruzzo region

Background

Listeriosis is a life-threatening disease in human as well as animals, cows and sheep are the most sensible to the disease. Correlation to feed is well documented (silage). Some clonal complexes (CCs) are more virulent than others and frequently involved in animal and human listeriosis. Whole genome sequencing (WGS) and in silico CCs identification and core genome multilocus sequence typing (cgMLST) determination are the best way to characterize isolates and confirm connection between clinical strains and source of contamination. This work aimed to demonstrate the advantages of using WGS to find the source of Listeria monocytogenes (Lm), causing an outbreak in an ovine farm in Abruzzo region.

Methods

Lm was detected according to ISO 11290-1:2017. Serogroup was determined by multiplex PCR. WGS data were obtained using Illumina platform. Sequences were used to assess CCs and cgMLST according to BIGSdb Pasteur platform. Two brain samples and 1 lymph node from 2 sheep, one sample of silage (15 analytical portion), and 1 sample of hay were tested.

Results

Lm was detected in all animal specimens and in 2 analytical portions of feed (silage) tested. Out of 35 colonies detected 28 were identified as Lm (27 serogoup IVb and 1 sample of silage serogroup IIa). Five colonies were selected for WGS (one from each animal brain, one from the lymph node and one from each positive analytical portion of silage), among them only one colony from the silage showed the same CC of the strains isolated from sheep (CC1). cgMLST revealed no allelic distances between these strains.

Conclusions

CC1 is the main virulent clone among Lm isolates often involved in human and animal outbreak. Feed may be a vehicle for Lm and could be the outbreak source. Cases ceased after removing the silage. Use of WGS is a definitive help in source attribution when feed is available and the sampling is done in a correct manner.

Key messages

Silage can be cause of listeriosis in livestock. WGS can improve source attribution of outbreaks detecting the relatedness of the strains and improving the epidemiological investigation in case of outbreak.

Shiga-toxin producing Escherichia coli detection in samples from Abruzzo and Molise regions, Italy

Background

Top five serogroups (O157, O111, O26, O103 and O145) of Shiga-toxin producing Escherichia coli (STEC) represent the third most important increasing zoonosis reported in European Union. The ISO methods of analysis, used in foods and environmental samples, quite often does not confirm the molecular detection of STEC genes (stx1 and stx2) in enrichment broth. The aim of this study was to summarize the results of the tests carried out at Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise in the last six years (2016-2021), comparing genes detection in enrichment broth and in colonies grown on agar plates.

Methods

Along the 2016-2021, a total of 1716 foods and environmental samples from Abruzzo and Molise regions were tested, according to ISO/TS 13136:2012.

Results

Out of 1716 samples, 16 (0.9%) shown presumptive positive presence of STEC (stx1 and/or stx2) in broth. In spite of that, the presence of STEC (positive colonies for stx1 and/or stx2) was confirmed only in 4 out of 16 samples (one sample of cheese and 3 of minced meat). Then, eae gene was found in 54 samples in broth and only in 3 samples from colonies, during a foodborne outbreak investigation. Serogroup specific targets were detected in 6 broth samples (O26, O145 and O157) and confirmed in colonies only in 2 minced meat samples (O157).

Conclusions

STEC are a heavy hazard for the consumers and the number of cases is slightly increasing since 2015. Our results highlight a low number of presumptive positive samples and even lower number of STEC detection obtained with the ISO classical method. Furthermore, detection of the target genes in broth was rarely confirmed after plating, highlighting a weak point of the analytical method that needs to be investigated. Efforts are necessary to improve the method and the STEC confirmation from colonies. Immunomagnetic beads targeting the top five serogroups and digital PCR could help in increasing the recovery rate of cultivable STEC.

Key messages

The presumptive positive samples for STEC genes in foodstuffs from the Abruzzo and Molise regions are quite rare, even lower is the number of confirmed colonies by agar plate isolation. Specific immunomagnetic beads for the top five STEC serogroups could improve the method and the STEC colonies detection, increasing the recovery rate of cultivable strains.

Foodborne outbreaks surveillance in hospitals and nursery homes: investigation on catering data

Background

Healthcare associated foodborne outbreaks (HA-FBO) can result from exposure to contaminated food in premises where highly vulnerable patients are cared, including hospitals and nursery homes. The probability of developing severe foodborne diseases such as invasive listeriosis is much higher for susceptible populations. There is limited knowledge on the data on food exposures that could be used to investigate HA-FBOs. There is also lack of data relating to specific policies in the health facilities aimed to prevent the administration of potentially risky foods, possibly bringing them from home.

Methods

This study was in the framework of One Health EJP Project NOVA. A semistructured questionnaire was administered to 4 general hospitals, 1 specialist clinic and 3 nursing homes located in the Abruzzo and Molise regions, Italy. The questionnaire included 25 questions in 3 sections (I. General organization of the catering service; II. Food menu data; III. Food from home).

Results

In most facilities (75%) external catering companies used in-house kitchens. Trace-back of food to individual patients was possible in 5 premises out of 8 (62.5%), but only in 1 nursery home out of 3 (33.3%). Data were collected in electronic format (hospitals) or paper (nursery homes) and stored 1-12 months. Food at risk of Listeria monocytogenes were not excluded from the menus, such as pre-sliced cooked meat products (served in 4 out of 8 premises, 50%), smoked fish (20%), soft cheese (20%). The consumption of food brought from home was possible in “special occasions”, mostly in the nursery homes (66.6%).

Conclusions

In case of HA-FBO it could be difficult to trace back the food particularly in the nursery homes where food data are not individually collected and usually on paper. More studies are needed in order to understand the effective exposure to foodborne pathogens, given that some types of foods considered by EFSA as at high risk of microbial contamination are commonly served.

Key messages

Served food could not be traced back to the patient mostly in nursery homes. Foods at risk of Listeria monocytogenes contamination are commonly served to patients and residents.

Klebsiella pneumoniae in vegetable products: antimicrobial resistance and consumer health risk

Background

Klebsiella pneumoniae (Kp) is considered one of the major causes of human hospital infections. Moreover, Kp is often present in several food products and it could be a potential health hazard for the consumers through the increase of Kp antimicrobial resistance (AMR) to the main routinely used antibiotics classes. The aim of this study was to evaluate the AMR profile of Kp strains isolated from vegetable food products.

Methods

The whole genome sequences of 10 Kp strains, previously isolated from carrots (n. 4), salads (n. 3), tomatoes (n. 2) and pumpkin (n. 1) samples, were obtained by next generation sequencing technique, using Illumina platform. Phenotypic and genotypic AMR profiles, with particular attention to β-lactams, quinolones and aminoglycosides resistances, were acquired by both agar diffusion and micro-dilution susceptibility testing and uploading the Kp sequences to Institut Pasteur platform (https://bigsdb.pasteur.fr/), respectively.

Results

Most of Kp strains (9 of 10) resulted susceptible to the main antibiotics tested and few AMR genes were detected in silico besides the native blaSHV, blaOKP and blaLEN. Only one Kp harboured blaAMPC and blaCMY, showing resistance to 5 β-lactams (amoxicillin/clavulanate, cefoxitin, cefpodoxime, cefpodoxime/clavulanate, ceftobiprole). Regarding the quinolone resistances, all the Kp strains carried gyr and par genes. No aminoglycoside resistance genes were highlighted in the 10 Kp strains studied.

Conclusions

These preliminary results showed the presence, in vegetable foods, mainly in ready to eat raw products, of Kp strains, harbouring no or few AMR genes. Good hygiene practices should be properly applied during the entire food processing chain, to avoid hazardous implications for the consumer. Further studies are needed in order to: analyse more vegetable samples, deeply evaluate the phenotypic and genotypic AMR profile of the Kp strains and their possible transmission from food products to consumer.

Key messages

Klebsiella pneumoniae is often isolated in food, as ready to eat vegetables, and it could be a potential public health risk due to the antimicrobial resistance increase to main antibiotics. The presence of Klebsiella pneumoniae in food implies the correct application of good hygiene practices in the entire food processing chain, in order to avoid dangerous effects for consumers.

Application of the Micro Biological Survey analytical method for the determination of bacterial load in cow raw milk

The aim of this study was to evaluate the performance of "Micro Biological Survey - MBS Test" in the enumeration of bacterial load in cow raw milk. The MBS test is based on a colorimetric method recently developed and patented by "Roma Tre" University, Italy. The evaluation of the performance of the MBS method was carried out by comparison with plate count at 30°C (gold standard) and flow cytometry. Thirteen independent set of experiments were performed analyzing a total of 104 samples of cow raw milk with the selected methods. Results obtained using the MBS method are comparable with those obtained with the plate count method at 30°C (CFU/mL) and flow cytometry technology; in particular, the results obtained with the MBS method are very close to plate count's at 30°C. On the other hand, there are statistically significant differences between these two methods' and flow cytometry technology's results that could be due to the different experimental conditions.

Excisional penetrating keratoplasty for fungal interface keratitis after endothelial keratoplasty: surgical timing and visual outcome

PURPOSE

In this paper, we describe two cases of fungal interface infectious keratitis (IIK) developed after endothelial keratoplasty (EK) who underwent delayed therapeutic penetrating keratoplasty (TPK) with a poor visual outcome. Furthermore, we conducted a review of the literature and analyzed the visual outcomes of TPK in relation to the time from IIK diagnosis.

METHODS

We searched the literature for fungal IIK cases occurred after EK and treated by TPK. We identified 17 cases of fungal IIK, mostly caused by Candida spp. (88%).

RESULTS

Infection was diagnosed at a median time of 21 (range 1-90 days) days after EK. The median lag time between infection diagnosis and TPK was 30 (range 7-393) days. The median distance corrected visual acuity (DCVA) measured 4-12 months after surgery was 20/40 (range 20/200-20/20). When TPK was performed within one month from diagnosis, the final median DCVA was 20/30 (range 20/100-20/20), with 83% of patients achieving ≥ 20/40 vision. When TPK was carried out later, the final median DCVA was 20/50 (range 20/200-20/22) with 44% of patients achieving ≥ 20/40 vision. One patient in the early surgery and four patients in the late surgery group showed postoperative DCVA ≤ 20/100 despite clear grafts.

CONCLUSION

TPK with removal of the sequestered infection is advocated as a safe and effective measure to treat a post-EK infection. Early surgery allows a reduced exposure time to infection and therefore may result in better visual outcomes and lower risk of complications caused by prolonged inflammation.

Multidrug-resistant Klebsiella pneumoniae: risks to food safety and public health

Background

Klebsiella pneumoniae (Kp) is a Gram-negative hospital-acquired pathogen. Kp also poses a potential food safety hazard, since a significant increase of multidrug-resistant (MDR) Kp was observed in foods. The purpose of this study was to characterize MDR Kp strains in order to evaluate the presence of beta-lactams, quinolones and aminoglycosides resistance genes.

Methods

A total of 13 Kp strains, isolated from chicken (n.8), raw milk (n.2), waste water (n.2), human faeces (n.1), and identified as MDR by microdilution test, were selected to evaluate antimicrobial resistance profiles, focusing on beta-lactams, quinolones and aminoglycosides. Next Generation Sequencing (NGS), with NextSeq 500 Illumina platform, was performed to acquire genome sequences. The antimicrobial resistance profiles were obtained using ResFinder (https://cge.cbs.dtu.dk/services/ResFinder/).

Results

From the 13 Kp considered, 6 strains (46.2 %) showed the presence of several beta-lactam genes. The blaSHV gene was carried by 12 Kp (92.3%); of these strains, 5 also carried blaTEM (41.7%) and 3 also blaCTX-M (25.0%) genes. Only 1 Kp strain showed the presence of blaOKP-A gene. All the 13 Kp carried the oqxA and oqxB genes. Of these strains, 4 also highlighted the presence of qnrB or qnrS plasmid-mediated gene for quinolone resistance. Regarding aminoglycoside resistance, 6 Kp strains (46.2%) carried aph, aadA and aaC genes, linked to gentamicin and streptomycin resistance protein.

Conclusions

These preliminary results emphasize the need of further studies on more several samples, to better understand the antimicrobial resistance of Kp strains, the hypothetical transmission of MDR Kp from foods to consumers and the potential risk posed to food safety, environmental and public health.

Key messages

The increasing prevalence of multidrug-resistant Klebsiella pneumoniae requires the need to investigate more foods and environmental samples to ensure consumer safety and public health. Public health safety requires a major knowledge of the hypothetical mechanisms and routes of transmission of multidrug-resistant Klebsiella pneumoniae.

Detection of Klebsiella pneumoniae complex in carrots

Background

Klebsiella pneumoniae (Kp) is an opportunistic pathogen now acknowledged as an urgent threat to human health because it is multi-drug resistant bacteria. The role of food as reservoir or carrier of Kp is under investigation, at the same time the optimization of the method to detect Kp in food is ongoing. The study was aimed to detect Kp in carrots using conventional method and to screen Real-time PCR performances, targeting intergenic sequence between zur and khe, based on INRA and Pasteur Institute method

Methods

A total of 60 samples of carrots were tested. The samples (25 g) were added to 225 ml of Buffered peptone water and incubated at 37 °C and at 44 °C for 24h. After incubation broths were subjected to Real-Time PCR, and one loop streaked on SCAI + inositol agar. Plates were then incubated at 37 °C and at 44 °C for 48 h. After incubation a maximum of 5 typical colonies were selected, subcultered on Nutritive agar and identified by MALDI-TOF MS.

Results

The RT PCR gave 29 positive samples, according to the presence of Kp detected at least in one of the two temperature conditions of broths incubation and 31 negative samples. Conventional culture gave, instead, 13 positive and 47 negative samples. Discordance was highlighted in 16 samples, all positives in RT-PCR and negatives with culture method.

Conclusions

Real-Time PCR gave not false negative results, then PCR decrease the time needed to perform the detection in negative samples. The discordance of results could be linked to lack of selectivity of the SCAI agar + inositol, not able to distinguish colonies of Klebsiella spp. Vs similar colonies not Klebsiella spp., the presence of DNA and not viable cells. The process of validation of the detection method is still ongoing, trying to improve selectivity using two selective media for plating. It's necessary to do new trials and to select more typical colonies to increase the probability to detect Kp colonies.

Key messages

Real-Time PCR is able to detect all positive samples, and to shorten the length of the analytical method. To improve sensibility of the analytical method more selective media need to be used.